feat: konfigurierbarer Dateiname + Archiv-Modus für Original (v0.3.0)

Neue [output]-Section:
- name_mode: prefix | suffix | none (suffix wird vor Extension eingefügt)
- name_tag: verbatim einfügbarer String
- original_on_success: delete | archive
- archive_dir mit Kollisions-Schutz (Timestamp-Suffix)

20 neue Tests (50 insgesamt, alle grün).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_once_exit_code.py

@@ -8,7 +8,7 @@ from pdf_ocr_hotfolder.processor import ProcessResult
 from pdf_ocr_hotfolder.service import HotfolderService
 
 
-def _fake_success(src: Path, working_dir, outgoing_dir, error_dir, ocr_cfg, vera_cfg):
+def _fake_success(src: Path, working_dir, outgoing_dir, error_dir, **kwargs):
     out = outgoing_dir / f"OCR_{src.name}"
     out.parent.mkdir(parents=True, exist_ok=True)
     out.write_bytes(b"%PDF-1.4 ocr\n")
@@ -16,7 +16,7 @@ def _fake_success(src: Path, working_dir, outgoing_dir, error_dir, ocr_cfg, vera
     return ProcessResult(src, out, True)
 
 
-def _fake_failure(src: Path, working_dir, outgoing_dir, error_dir, ocr_cfg, vera_cfg):
+def _fake_failure(src: Path, working_dir, outgoing_dir, error_dir, **kwargs):
     error_dir.mkdir(parents=True, exist_ok=True)
     dest = error_dir / src.name
     src.rename(dest)